Prevalence and molecular characterisation of extended-spectrum β-lactamases genes in Escherichia coli and Salmonella spp. isolated from fish samples in Chhattisgarh, India


Abstract
coli and Salmonella spp. Out of 200 samples collected from retail markets of Durg, Raipur, Rajnandgaon and Balod
districts of Chhattisgarh State, 76 (38) and 46 (23%) samples were found contaminated with E. coli and Salmonella spp.,
respectively. Multiple antibiotic resistant (MAR) index varied between 0.00 to 0.88 and 0.11 to 0.88 for E. coli and Salmonella
isolates, respectively. The isolates were screened phenotypically for ESBL production and multiplex PCR targeting blaTEM,
blaSHV, andblaCTX-M genes, was carried out followed by sequencing. Prevalence of blaTEM, blaSHV and blaCTX-M genes in E.
coli and Salmonella isolates were found to be 13.2, 1.3, 0 and 6.5, 0, 4.4%, respectively. Higher percentage of resistant
genes was detected in plasmid DNA in comparison to genomic DNA. Sequencing of PCR amplicons of blaTEM and blaCTX-M
genes revealed the presence of blaTEM-116 and blaCTX-M-15 variants, respectively. The study indicates the presence of multidrug
resistant ESBL producing E. coli and Salmonella in fish samples, which may pose threat to the fish consumers.
Keywords: blaTEM, blaSHV, blaCTX-M, E. coli, Fish, MAR index, Salmonella